Crystallization and preliminary diffraction analysis of the phosphatase domain of PTPN14 in the human papillomavirus E7 binding-defective mutant form

A tumor suppressor protein PTPN14 interacts with the oncoprotein E7 of human papillomaviruses, leading to its proteasomal degradation. Introduction of F1044S, G1055Q, and E1095A mutations into its phosphatase domain restored the antitumor activity by impairing the interaction with E7, showing the therapeutic potential of this mutant form against human papillomavirus-involved cancers. In this study, the phosphatase domain of PTPN14 containing the three mutations was produced in an Escherichia coli expression system, purified using Ni-NTA affinity and size exclusion chromatographies, and then crystallized. X-ray diffraction data with a maximum resolution of 1.50 Å were successfully collected, and a preliminary diffraction analysis was conducted. Our crystals belonged to the P21 space group with unit cell parameters of a = 43.9 Å, b = 74.3 Å, c = 47.8 Å, and β = 102.0°. The asymmetric unit contains one protein molecule with a 45% solvent content and a 2.2 Å3/Da Matthews coefficient.